Dialog enhancement is about enhancing dialog in relation to other audio content. This may for example be applied to allow hearing-impaired persons to follow the dialog in a movie. For channel-based audio content, the dialog is typically present in several channels and is also mixed with other audio content. Therefore it is a non-trivial task to enhance the dialog.
There are several known methods for performing dialog enhancement in a decoder. According to some of these methods, the full channel content, i.e. the full channel configuration, is first decoded and then received dialog enhancement parameters are used to predict the dialog on basis of the full channel content. The predicted dialog is then used to enhance the dialog in relevant channels. However, such decoding methods rely on a decoder capable of decoding the full channel configuration.
However, low complexity decoders are typically not designed to decode the full channel configuration. Instead, a low complexity decoder may decode and output a lower number of channels which represent a downmixed version of the full channel configuration. Accordingly, the full channel configuration is not available in the low complexity decoder. As the dialog enhancement parameters are defined with respect to the channels of the full channel configuration (or at least with respect to some of the channels of the full channel configuration) the known dialog enhancement methods cannot be applied directly by a low complexity decoder. In particular, this is the case since channels with respect to which the dialog enhancement parameters apply may still be mixed with other channels.
There is thus room for improvements that allow a low complexity decoder to apply dialog enhancement without having to decode the full channel configuration.
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